standard dual battery isolation

[Old.Tony]

You won't need to put a fuse in the tub if there's no battery in the tub. Fuses only need to go at the battery before a long cable and at the device to protect the device.

If you have a battery in the tub and one up front, then you'd fuse both ends.

Gels hate heat and even slight overvoltages. I'm over using gel batteries. Next time I want to throw a large amount of money at a battery I'll get an AGM. If I want to get better power for my $ I'll just get an ordinary deep cycle - much cheaper, throw it out after 2 years you're still saving money.

Krafty's right on the charge amount too. The alternator won't ever fully charge the battery and you should never fully discharge ANY lead-acid battery. Your alternator should give you about 75% charge. A starter should never be discharged below 50% so you've got 25% to play with - with a typical starter that's 0.25*70=17.5Ah. Not much - but just enough. Use it more and kill it faster then replace it with an AGM that can be discharged to 20% of its capacity. Charged with the alternator you'll have 75-20 = 55% usable capacity. of course, charged with an inverter + charger you'll have 80% usable capacity but that's another discussion.

 

[KraftyPg]

Now if only I actually believed the partially charging battery theory of the world I could be both right and wrong at the same time.

 

[Old.Tony]

Krafty, it comes from the voltage applied to the battery. At 14.7V you're just not quite giving it enough volts to get it to fully charge in a short time - it takes quite a while. CTek used to have some great info on their home page about this, but I think BatteryUniversity would be a good place to go look, as well as Collyn Rivers' articles, in particular the 70% Debate article.

I could repeat that here - but it boils down to how long you have to charge the battery at 14.7V in order to get the battery to 100% charge. At 14.7V the battery won't gas (fizz) like mad - thus conserving electrolyte.

 

[Joshp82]

Ok so if I want to get 100% charge ill need a decent charger. That I can hook up over night. Can anyone recommend a good one? Also what size inverter should I be looking at to charge my cordless drills, laptop and camera batteries?

Sent from Josh's iPhone using Forum Runner

 

[Old.Tony]

It greatly depends on the power requirements of each of those. I have a netbook that only needs 36W to charge its battery while it's running, and a laptop that consumes 94W while running. You can get 12V cordless drills that charge @ 2A (24W) and 20V drills that charge at 3.5A (70W).

Worst case: 100W laptop, 100W drill, say 50W for the camera battery (way over the top on that) and give it an extra 50W - that's 300W. To make sure you're not too close to the constant capacity of the inverter, get a 400W unit. If you buy it from Jaycar it'll be electrically isolated (the best and safest type).

They do recommend that you only have one item plugged into an inverter at a time though - although I think that refers to earthed items only.

 

[Joshp82]

Oh ok I was looking at 1000w inverters. So I don't need one that big?

Sent from Josh's iPhone using Forum Runner

 

[Old.Tony]

You couldn't use a 1000W inverter in the cabin anyway. Cabin power is limited to 20A @ 12V anyway, which is about 240W. Your 400W inverter will be pushing the boundaries of the fuse and wiring - a 1000W inverter will definitely take it over the top!

If you have a need for that much inverted power elsewhere (and not at the same time) then by all means buy one, but I don't think it needs to be that large to power the items you're looking at.

 

[Joshp82]

Ok thanks. The inverter would stay in the tub. I'll check the specs on my chargers today to see what size inverter I'll need.
Thanks for you help

Sent from Josh's iPhone using Forum Runner

 

[KraftyPg]

Also what size inverter should I be looking at to charge my cordless drills, laptop and camera batteries?

My fridge has a single outlet 300W inverter built in and it charges anything from laptops, to sat phones to the 18V drills however I rarely use it for such these days.

If I need to charge the crappy or the tablet I use a Jaycar laptop power supply plugged into the aux, it comes with several different plugs for different model crappies and I had to modify one for the tablet but it works without effort and requires no installation.

Sat phones I rarely use and drills etc these days are powered by the gennie on the trailer that we tow around the farm so the inverter in the fridge is almost obsolete for me but unless you really want high power items I'd suggest 1000W is a little excessive.

 

[maulbeagle]

Cable route ?

Hi guys,
where/how did you route the cable from the second battery to the tray ?
Just looking for the best/easiest way to run the cable and hoping to learn from your experiences !

Thanks,
Paul

 

[KraftyPg]

Depends on the model, some used the tub holes, some have used the tail light holes, some may even have made their own holes. Most have probably gone down the chassis rails. though I went down the inside of the cab but once again model specifics might make a difference.

 

[maulbeagle]

OK thanks for the help

 

[Joshp82]

hi again
ive been lretty slack and havent done a thing to my ute. Im in the process of running power to my tub. i have some 8gage cable from an old stereo install. Will this be big enough for when i put a deep cycle battery in the tub or will i need 4gage? at the moment im just running the 12v power for some lights for a camping trip in a couple of weeks but to save time in the ling run should run larger cable?
thanks
Josh

 

[maulbeagle]

Struggling

Guys,

I've spent some time under the Nav (2011 D22) lately looking at how to get the cables in or along the chassis rails. my preference is for inside the chassis rails if possible so they aren't exposed to damage.
However I can't find a way to get my fish tape through the rails, they seem to be blocked no matter how I try.
Has anyone got their cable running inside the chassis rails from engine bay to tub or towbar ?
And if not, what type of fixings are you using to secure the cable (I'm looking at running 6B&S) to the outside of the chassis rails ? I know I can't drill the chassis rails but there are holes everywhere I should be able to screw into ?

Cheers,
Paul

 

[sparra04]

i ran mine on top of chassis rail
protected in flex conduit
then cable tied it

 

[bods]

same, i just cable tied mine along the fuel and brake lines on the driver's side rail. then went into the tub above where the fuel filler comes out, there are holes at the front of the tub at the side under the lip

 

[maulbeagle]

thanks for the replies bods and sparra. how long has your cable been fixed there ? just wondering about the longevity of the cable ties ? do you inspect it every now and then or just trust that they haven't broken ?

and is there any way that the top of the chassis rail could contact the bottom of the car body ? i guess not or the fuel lines wouldn't be there !

thanks

 

[bods]

just trust them, lol. nah, the factory wiring looms are only attached with plastic cable ties with clips on the end of them into the chassis rail anyway and there's probably a lot more weight in them than just a single cable to put power to the tub. mines been there a good 6 months now and no probs but i haven't really been offroad in that time. in saying that it's far enough up out of the way that it won't get caught on anything without destroying something else first...

i guess there is a slight possibility of the body contacting the chassis, but the body mounts on the chassis would probably have to break off first. you never know though, haha

 

[d22dave]

just wondering about the longevity of the cable ties ?

As long as you use a decent size i,ve never had a problem, The only time i,ve ever had a broken one is if i put a little pissy size tie in. My power cables from my second battery under the bonnet to my power sockets in the tub are in convoluted split tubing and cable tied to the chassis, Been like that for 2 years now

 

[sparra04]

mines been there 2 years
and its been through some extreme 4wdriving
still ok, i check every now and then
i ran mine up into tail light
use big cable ties and you will be ok